1. Field of the Invention
The present invention relates to a semiconductor device and a method for producing the same, and particularly to a semiconductor device having a thin-film resistor to be trimmed by laser and a method for producing this sort of semiconductor device.
2. Description of the Related Art
In an insulation film of a semiconductor device having an integrated circuit, there is arranged a metallic thin-film resistor. The thin-film resistor is fused at a predetermined location by laser beam to adjust the resistance value thereof.
FIG. 1 shows a conventional semiconductor device comprising an integrated circuit. In the figure, a field insulation film 50 is formed on the surface of a semiconductor substrate in a process in which a PN junction region for circuit elements is formed. A thin-film resistor 90 is formed on the field insulation film 50. Then, after a passivation film is formed on the thin-film resistor in the semiconductor device, the thin-film resistor 90 is irradiated with a laser beam through the passivation film to be trimmed by removing a part of the thin-film resistor.
A process of adjusting the resistance value of the thin-film resistor 90 is called laser trimming. An important thing for the laser trimming is to adjust a quantity of laser energy to be absorbed by the thin-film resistor 90 to an optimum level. If the absorbed energy is too little, the thin-film resistor will fuse insufficiently, and if it is excessive, the insulation film 50 and semiconductor substrate will be damaged.